 datatypes xs="http://www.w3.org/2001/XMLSchema-datatypes"
 element library { 
  element book {
   attribute id {xs:NMTOKEN},
   attribute available {xs:boolean - (xs:boolean "false")},
   element isbn {xs:NMTOKEN},
   element title {attribute xml:lang {xs:language}, xs:token},
   element author {
    attribute id {xs:NMTOKEN},
    element name {xs:token},
    element born {xs:date},
    element dead {xs:date}?}*,
   element character {
    attribute id {xs:NMTOKEN},
    element name {xs:token},
    element born {xs:date},
    element qualification {xs:token}}*
  } +
 }
